#swallow  small long-winged songbird noted for swift graceful flight and the regularity of its migrations
  supertype:  #oscine_bird__oscine  passerine bird having specialized vocal apparatus
  subtype:  #barn_swallow__chimney_swallow__chimneyswallow__Hirundo_rustica  common swallow of North America and Europe that nests in barns etc.
  subtype:  #cliff_swallow__cliffswallow__Hirundo_pyrrhonota  North American swallow that lives in colonies and builds bottle-shaped mud nests on cliffs and walls
  subtype:  #tree_swallow__tree_martin__Hirundo_nigricans  of Australia and Polynesia; nests in tree cavities
  subtype:  #white-bellied_swallow__whitebelliedswallow__tree_swallow__Iridoprocne_bicolor  bluish-green-and-white North American swallow; nests in tree cavities
  subtype:  #martin  any of various swallows with squarish or slightly forked tail and long pointed wings; migrate around Martinmas
     subtype:  #house_martin__housemartin__Delichon_urbica  common small European martin that builds nests under the eaves of houses
     subtype:  #bank_martin__bank_swallow__sand_martin__Riparia_riparia  swallow of the northern hemisphere that nests in tunnels dug in clay or sand banks
     subtype:  #purple_martin__Progne_subis  large North American martin of which the male is blue-black

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